Key board printer

ABSTRACT

A keyboard printer for use as a peripheral element of a computer in which the codes of the characters are key pulses exhibiting with respect to a start pulse variable discrete phase-shifts. This printer comprises means for continuously rotating a first wheel with one magnetic tooth defining a start pulse in each rotating cycle, a second wheel with a plurality of magnetic teeth defining a plurality of character pulses in each rotating cycle and a rotative arm carrying a mobile electrode. A key pulse distributor comprises a common electrode and individual character electrodes. The keys are formed by two adjacent key electrodes which exhibit a small capacitance when not touched and a large capacitance when touched by the operator&#39;&#39;s finger tips. The key pulse distributor produces key pulses during several cycles since the time during which the operator&#39;&#39;s finger tip is on the key is longer than the rotation cycle duration of the printer. Means are provided for gating only one key pulse out of a series of identical key pulses.

United States Patent Gloess [451 July 25, 1972 [54] KEY BOARD PRINTER 2,805,620 9/1957 Rosen et al. ..101/93 C Inventor: Paul F. chess H4 Avenue Andre 3,142,247 7/1964 Sweeney ..197/18 X Morizot, Boulogne-Bilancourt, France Primary Examiner Edgar S. Bu"

[22] Filed: Aug. 13, 1970 Assistant Examiner-R. T. Rader [30] Foreign Application Priority Data Aug. 14, 1969 France ..6927998 [51] Int. Cl. ...B4lj 23/04 [58] FieldofSearch ..l97/18,49,53,98, 107; 101/93 [56] References Cited UNITED STATES PATENTS 3,589,494 6/1971 Gloess ..197/18 3,454,147 7/1969 Schrem... .....l97/107 X 3,289,806 12/1966 Manus .....l97/107 X 3,232,404 2/1966 Jones... ...10l/93 C X 2,782,308 2/1957 Rug ..197/93 UX 3,332,068 7/1967 McLaughlin et al. ..101/93 C X 3,289,805 12/1966 Kleinschmidt et a1. ..197/53 X Attorney-Abraham A. Saffitz [57] ABSTRACT A keyboard printer for use as a peripheral element of a computer in which the codes of the characters are key pulses exhibiting with respect to a start pulse variable discrete phaseshifts. This printer comprises means for continuously rotating a first wheel with one magnetic tooth defining a start pulse in each rotating cycle, a second wheel with a plurality of magnetic teeth defining a plurality of character pulses in each rotating cycle and a rotative arm carrying a mobile electrode. A key pulse distributor comprises a common electrode and individual character electrodes. The keys are formed by two adjacent key electrodes which exhibit a small capacitance when not touched and a large capacitance when touched by the operator's finger tips. The key pulse distributor produces key pulses during several cycles since the time during which the operators finger tip is on the key is longer than the rotation cycle duration of the printer. Means are provided for gating only one key pulse out of a series of identical key pulses.

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if? ig T @1 2 A1 START KEY CHARACTER PULSE PULSE PULSE TERM/NA L TE RM/NAL TE RM/NAL KEY BOARD PRINTER This invention relates to an office typewriter the movements of which are controlled electrically by a keyboard having nonmovable keys of the capacitative type.

This typewriter is derived from a computer printing machine having a keyboard with capacitative keys, as described in copending US. Patent application Ser. No. 818626 now U.S. Pat. No. 3,589,494 Filed Apr. 23, 1969 in the name of the present Applicant.

This printing machine comprises two main units:

A mechanical unit which receives a continuous rotation from an electric motor, whose shaft bears a type wheel, two phonic wheels and the arm of a signal distributor; and a printed circuit unit providing two essential components: a signal distributor and the keyboard comprising the nonmovable keys of the printing machine.

More precisely:

a. the type wheel consists of a ring of flexible strips rigidly connected to the same base and the end of each strip bears a character formed by stamping. A character is printed on a sheet of paper by striking the corresponding strip with an electromagnetically controlled hammer.

b. the first and second phonic wheels provided with teeth of magnetic material energize windings on magnetic cores by induction, thus producing pulses of a suitable frequency which are fed to the computer.

0. the printing of a character is controlled by a signal which leaves the computer at a time having a given delay with respect to a reference pulse, by a counting program, from the numerical equivalent of the character, program synchronization being obtained by the signals produced by the phonic wheels.

d. The keys of the keyboard have two electrodes which between them have a capacity which is modified by the contact of a finger on the key.

e. the signal distributor connected to the keyboard forms with the latter a two-sided printed circuit on a flexible and malleable plastic support and is a cylindrical member associated with the mechanical continuously rotating unit by an arm whose metal end produces capacitative effects when it passes over the metal zones printed on the inner wall of the distributor and associated with the keys and forming radial electrodes. This movement feeds electrical signals to the keys. The distributor comprises an annular input electrode receiving the signals from one of the phonic wheels and as many radial electrodes as there arekeys in the printing machine keyboard so that for each revolution of the distributor arm each key receives a pulse corresponding to the angular position of the radial electrode in question by coupling of the annular electrode successively to the radial electrodes by means of said arm.

f. A compensating system is provided so that in the absence of any finger contact on a key no signal is present on the keyboard collector electrode, but finger contact on the key results in a key pulse on the keyboard collector electrode; it is repeated on this electrode on each distributor revolution as long as there is finger action on the key and is also communicated to the computer.

The prior art printing machine produces the following signals:

A start pulse" delivered by the first phonic wheel on each revolution of the motor.

Character pulses delivered by the second phonic wheel and distributed equally throughout the cycle.

Key pulses coinciding with a character pulse when the operator places his or her finger on the key associated with said character.

The main object of the invention is to allow the prior art printing machine to operate as a typewriter or locally print the text that it is transmittinG with it is used as a transmission printing machine.

The prior art printing machine as indicated above converts each character into a pulse which is coded with a time position which varies in the cycle, the delay between said pulse and a cycle start pulse forming the code characteristic. Since the machine cycle is very short, e.g. one-twentieth of a second, and since the application of the operator's finger to a key lasts for several cycles, only the key pulse occurring during a single cycle must be retained as the printing or striking signal or as the machine function control signal. This is achieved by interposing between the machine outputs delivering the start, character and key pulses, on the one hand, and the strike and function mechanisms, on the other hand, a selection circuit which retains only one key pulse from a plurality of recurrent pulses and distinguishes the key pulses associated with characters from the key pulses associated with functions.

The invention will now be described in detail with reference to the accompanying drawings wherein:

FIG. 1 is a perspective view in simplified form and partially in the form of a block diagram, showing one embodiment of the typewriter according to the invention.

FIG. 2 is a detailed diagram of the logic circuit controlling the striking of the characters of the typewriter according to the invention.

FIG. 3 is a detailed diagram of the logic circuit controlling the striking of the characters and the performance of the functions and FIG. 4 shows the position of the function pulses in relation to the type pulses in the cycle.

Referring to FIG. 1, reference 1 denotes an electric motor which continuously rotates a type wheel 10, a phonic wheel 20 having a single tooth of magnetic material, a phonic wheel 30, the periphery of which has as many teeth of magnetic material as there are machine keys (characters and functions), and the rotor arm 41 of a distributor 40. The motor 1 rotates, for example, at 20 revolutions per second.

The phonic wheel 20 produces 1 pulse per revolution in the winding 22 on the magnetic core 23. In the example selected, the revolution pulses have a frequency of 20 Hz. The phonic wheel 30 produces a certain number of character (or function) pulses which are distributed equally in time during 1 cycle of revolution in the winding 32 on the magnetic core 33. Assuming that there are 50 teeth on the phonic wheel 30, the frequency of the type or function pulses is 1,000 I-Iz.

Reference 2 denotes a typewriter platen bearing a sheet of paper 3 and adapted to move longitudinally by a conventionally platen advance mechanism (not shown).

Reference 50 denotes the flexible printed circuit keyboard which is rigidly connected to the distributor 40 by the connecting strip 4.

The distributor 40 is a cylinder comprising an annular electrode 42 and a plurality of radial electrodes 43, to 43 The annular electrode 42 is connected to the winding 32. Each of the radial electrodes 43, to 43 is connected to a character or function key 51, to 51 The arm 41 bears a metal terminal plate 410 which establishes a selective capacitative coupling between the annular electrode and one of the radial electrodes depending upon its position during the cycle.

The keys are made in two metallized zones separated by an insulating gap, the machine operator placing the end of his or her finger on said keys. Key pulses are obtained at the output of the amplifier 60, each key pulse coinciding with the type pulse associated with the character marked on the key.

The logic circuit shown in FIG. 2 has three inputs, 100,, to which the start pulses are applied, 100 to which the key pulses are applied, and 100,, to which the type pulses are applied. The circuit 100 comprises three flipflops (bistable) 101, 102, 103 of conventional type, three AND gates 104, 105, 106, three delay lines 107, 108, 109, and an amplifier 110.

The system 100 operates as follows:

When the motor 1 of the typewriter is inoperative, no pulse is applied to the inputs 100,, 100 100;, of the system 100 and hence the flipflops 101, 102, 103 are in the zero state and the AND gates 104, 105, 106 are closed.

When the typewriter 1 is started and the operator is not using the keyboard 50, the system 100 does not come into The reason for this is that since the AND gate 106 remains closed, the character pulse from the winding 33 (FIG. 1) and applied to the terminal 100;, is inoperative. The same applies to the key pulse applied to the input 100 since the AND gate 105 is also closed.

As soon as the first start pulse is applied to the terminal 100,, the flipflop 101 passes from the zero state to the 1 state with a certain delay time T due to the presence of the delay line 107. The AND gate 104 directly receives the start pulse at one of its inputs and, at its second input, a voltage applied with a delay T by the bistable 101 when it passes from the zero state to the 1 state, and therefore remains closed. Since, however, the flipflop 101 remains in the 1 state, the AND gate 104 opens on the second revolution pulse.

The signal from the AND gate 104 brings the flipflop 102 into the 1 state and the flipflop 102 applies a voltage to the first input of the gate 105, this voltage being maintained.

The following start pulses no longer result in any change of the states of the flipflops 101 and 102 and consequently the AND gate 105 will pass a key pulse as soon as it is applied to the terminal 100 When the operator uses the typewriter according to the invention, the capacitative action of his or her finger on a key of the keyboard 50 will produce a key pulse at the tenninal 100 and this immediately brings the flipflop 103 into the 1 state, because, as indicated hereinabove, the AND gate 105 is open, and the flipflops 101 and 102 are brought into the zero state with a certain delay T produced by the delay line 108, so that the AND gates 104 and 105 are closed, T after the key pulse had passed through the AND gate 105.

The voltage from the flipflop 103 as a result of its changeover from the zero state to the 1 state is applied with a certain delay T due to the presence of the delay line 109, to the first input of the AND gate 106 which thus opens for a character pulse as soon as it appears at the terminal 100 As it leaves the AND gate 106, the said pulse actuates the strike electromagnet 11 as a result of the energy delivered by the amplifier 110 and returns the flipflop 103 to zero, thus closing the AND gate 106. Thus it is the character pulse following the key pulse which effects the striking operation As indicated hereinabove, since the key pulse has returned the logic system 100 to the initial state that is occupied when the typewriter was started, it follows that as long as the operators finger has not left the key of the keyboard 50 between two consecutive start pulses, the flipflop 102 will not be able to be returned to the I state and the following key pulses produced by the operator holding his or her finger on the same key will have no effect on the strike electromagnet 11.

AS soon as the operators finger leaves the key within the required time, the typewriter will be released and it will be possible for another character to be printed.

The electromagnet 11 could be controlled cirectly with a signal from the and gate 105 without the intervention of the character pulse, but there would then be the occasional risk of producing strike pulses which are cut as regards duration, in the event of any appreciable modification of the correct action of the finger during the period of the key pulse.

The delays T T T ofthe delay lines 107, 108, 109 may be of the order of some microseconds. More precisely, they should be greater than the duration of the character and start pulses and less than the interval of time between the revolution pulse and an adjacent type pulse. Since the start pulse occurs in the middle of the gap between two character pulses, the delays must be less than a half-cycle.

FIG. 3 illustrates a logic circuit 100 which is used to codify not only the characters but also the machine functions such as carriage return, line feed, spacing, letter-figure changeover, figure-letter changeover and so on. This logic circuit 100' comprises the same flipflops 101, 102, 103, the same gates 104, 105, 106, the same delay lines 107, 108, 109 and the same amplifier 110 as the circuit 100. It also comprises two additional flipflops 111, 112, two delay lines 113, 115, three AND gates 114, 116, 117 and an amplifier 118.

Like the characters, the functions are defined by a pulse having a delay characteristic of the function with respect to the cycle start pulse. To distinguish the character pulses from the function pulses, the function pulses must have a specific location in the cycle.

Line 1 in FIG. 4 illustrates the start pulse 1 and line 2 illustrates the carriage return pulse a which is situated just before the pulse t and the spacing pulse b which occurs just after the pulse 2. As has been indicated hereinbefore, the character pulses following the key pulses are the operative pulses, and the carriage return and spacing pulses have the locations a and b on line 3 in FIG. 4.

The flipflops 111 and 112 are brought into the 1 state by the start pulse 1 (lines 4 and 5 in FIG. 4). The flipflop 111 is returned to rest by the type pulse a (which is the carriage return function pulse) immediately following the revolution pulse 1 (by a half-cycle) and delayed in the delay line 113. The flipflop 112 is returned to rest by the second type pulse b which is the spacing function pulse) following the revolution pulse t by a 1% cycle and delayed in 114. The flipflop 111 opens the gate 117 and the flipflop 112 closes the gate 116. It will be seen that 116 is closed during the two time slots which follow the pulse t and which serve for the transmission of the carriage return function signal. All character signals (when there is a key signal coinciding with them) except for a and b' therefore leave by the output terminal 100,; the carriage return function signal leaves by the output terminal 100,, and the spacing signal leaves by the output terminal after passing through the amplifier 118. In this way, the carriage advances both when a type character is struck and when a space is struck. If it is required to transmit other function signals, 116 must be inhibited during the entire duration of the various function signals and other gates similar to l 17 must be provided and must each be opened for the duration of the cycle associated with a specific function signal.

In other words, the group of circuits 111-115 operates as a time slot distributor similar to those in multiplex systems and if there are more than two function signals the distributor would have to distribute as many time slots as there are functions (except for the spacing function which is specific).

WORDING ON DRAWINGS FIG. 3

100 start pulse 100 key pulse 100 character pulse FIG. 4

l start pulse 2. key pulse 3. character pulse following key pulse What] claim is:

l. A keyboard printer for use as a peripheral element of a computer comprising a character wheel, means for continuously rotating said character wheel and for selectively printing the characters without stopping of the wheel, means for distributing onto a plurality of start and character terminals a start pulse and character pulses, each character being defined by the delay between the start pulse and the character pulse, a plurality of touch-operated character keys each including first and second electrodes, connections between the first of said electrodes and said character terminals, an annular electrode, a rotating electrode sequentially and capacitively coupling said annular electrode to each one of a plurality of character electrodes each constituting one of said character terminals, connections between the second of said electrodes and an output terminal, said key electrodes exhibiting with each other a large capacitance when operators finger tip is on the key and a small capacitance when operators finger tip if off the key, whereby cyclical key pulses are produced at said key pulse terminal as long as operators finger tip is on the corresponding key, means for applying said key pulses to said selective printing means and inhibiting means inserted between said key pulse terminal and said applying means which includes a first gate having a first input directly connected to said start pulse terminal, a first flipfiop, a first delay line connected to said start pulse terminal and a second delay line connected to the key pulse terminal, said first flipfiop having its operative and reset inputs respectively connected to the said first delay line output and to the said second delay line output and having its operative output connected to the second input of said first gate, a second flipfiop having its operative and reset inputs respectively connected to said first gate output and to said second delay line output, a second gate having a first input directly connected to said key pulse terminal and a second input connected to said second flipfiop operative output, said second gate output being connected to said selective printing means.

2. A keyboard printer as set forth in claim 1, which includes second inhibiting means inserted between the said second gate output and the said selective printing means, said second inhibiting means including a third flipfiop having its operative input connected to said second gate output, a third delay line connected to said third flipfiop operative output, a third gate having a first input connected to said third delay line output and a second input connected to said character pulse terminal, said third gate output being connected both to said selective printing means and to said third flipfiop reset input.

3. A keyboard printer as set forth in claim 1, which includes operating means for implementing usual non-printing printer functions such as carriage return, such function operations being controlled by specific ones of the said key electrodes, each character pulse corresponding to the said function key electrodes being delayed by a predetermined time with respect to the start pulse, means for sending key pulses corresponding to said non-printing functions to said operating means instead of sending such key pulses to said selective printing means, said sending means including a fourth flipfiop having its operative and reset inputs selectively connected to said start pulse terminal and to a fourth delay line output, such a fourth delay line having its input connected to said character pulse terminal and providing a delay equal to the said predetermined time, a fifth delay line having its input connected to said fourth flipfiop reset output and its input connected to one input of a fourth gate and providing a delay corresponding to the function operation duration, said fourth gate having its second input connected to said fourth delay line output, a fifth flipfiop having its operative and reset inputs respectively connected to said key pulse terminal and to said fourth gate output, a fifth gate having a first input connected to said second gate output and a second input connected to said fourth flipfiop operative output, a sixth gate having a first input connected to said second gate output and a second input connected to said fifth flipfiop reset output, said fifth gate output being connected to said operating means and said sixth gate output being connected to said printing means. 

1. A keyboard printer for use as a peripheral element of a computer comprising a character wheel, means for continuously rotating said character wheel and for selectively printing the characters without stopping of the wheel, means for distributing onto a plurality of start and character terminals a start pulse and character pulses, each character being defined by the delay between the start pulse and the character pulse, a plurality of touch-operated character keys each including first and second electrodes, connections between the first of said electrodes and said character terminals, an annular electrode, a rotating electrode sequentially and capacitively coupling said annular electrode to each one of a plurality of character electrodes each constituting one of said character terminals, connections between the second of said electrodes and an output terminal, said key electrodes exhibiting with each other a large capacitance when operator''s finger tip is on the key and a small capacitance when operator''s finger tip if off the key, whereby cyclical key pulses are produced at said key pulse terminal as long as operator''s finger tip is on the corresponding key, means for applying said key pulses to said selective printing means and inhibiting means inserted between said key pulse terminal and said applying means which includes a first gate having a first input directly connected to said start pulse terminal, a first flipflop, a first delay line connected to said start pulse terminal and a second delay line connected to the key pulse terminal, said first flipflop having its operative and reset inputs respectively connected to the said first delay line output and to the said second delay line output and having its operative output connected to the second input of said first gate, a second flipflop having its operative and reset inputs respectively connected to said first gate output and to said second delay line output, a second gate having a first input directly connected to said key pulse terminal and a second input connected to said second flipflop operative output, said second gate output being connected to said selective printing means.
 2. A keyboard printer as set forth in claim 1, which includes second inhibiting means inserted between the said second gate output and the said selective printing means, said second inhibiting means including a third flipflop having its operative input connected to said second gate output, a third delay line connected to said third flipflop operative output, a third gate having a first input connected to said third delay line output and a secoNd input connected to said character pulse terminal, said third gate output being connected both to said selective printing means and to said third flipflop reset input.
 3. A keyboard printer as set forth in claim 1, which includes operating means for implementing usual non-printing printer functions such as carriage return, such function operations being controlled by specific ones of the said key electrodes, each character pulse corresponding to the said function key electrodes being delayed by a predetermined time with respect to the start pulse, means for sending key pulses corresponding to said non-printing functions to said operating means instead of sending such key pulses to said selective printing means, said sending means including a fourth flipflop having its operative and reset inputs selectively connected to said start pulse terminal and to a fourth delay line output, such a fourth delay line having its input connected to said character pulse terminal and providing a delay equal to the said predetermined time, a fifth delay line having its input connected to said fourth flipflop reset output and its input connected to one input of a fourth gate and providing a delay corresponding to the function operation duration, said fourth gate having its second input connected to said fourth delay line output, a fifth flipflop having its operative and reset inputs respectively connected to said key pulse terminal and to said fourth gate output, a fifth gate having a first input connected to said second gate output and a second input connected to said fourth flipflop operative output, a sixth gate having a first input connected to said second gate output and a second input connected to said fifth flipflop reset output, said fifth gate output being connected to said operating means and said sixth gate output being connected to said printing means. 